emacs/lisp/whitespace.el

;;; whitespace.el --- Warn about and clean bogus whitespaces in the file.

;; Copyright (C) 1999 Free Software Foundation, Inc.

;; Author: Rajesh Vaidheeswarran <rv@dsmit.com>
;; Keywords: convenience

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; Whitespace.el URL: http://www.dsmit.com/lisp/

;; Exported functions:

;; `whitespace-buffer' - To check the current buffer for whitespace problems.
;; `whitespace-cleanup' - To cleanup all whitespaces in the current buffer.

;;; Code:

;; add a hook to find-file-hooks and kill-buffer-hook
(add-hook 'find-file-hooks 'whitespace-buffer)
(add-hook 'kill-buffer-hook 'whitespace-buffer)

(defvar whitespace-version "1.9" "Version of the whitespace library.")
(defvar whitespace-indent-regexp (concat "^\\(	*\\)    " "    ")
  "Any 8 or more spaces that can be replaced with a TAB")
(defvar whitespace-spacetab-regexp " \t" "A TAB followed by a space")
(defvar whitespace-ateol-regexp "[ \t]$" "A TAB or a space at the EOL")
(defvar whitespace-errbuf "*Whitespace Errors*"
  "The buffer where the errors will appear")

;; Find out what type of emacs we are running in.
(defvar whitespace-running-emacs (if (string-match "XEmacs\\|Lucid"
						   emacs-version) nil t)
  "If the current Emacs is not XEmacs, then, this is t.")

;; For users of Emacs 19.x, defgroup and defcustom are not defined.

(if (< (string-to-int emacs-version) 20)
    (progn
      (defmacro defgroup (sym memb doc &rest args)
	t)
      (defmacro defcustom (sym val doc &rest args)
	`(defvar ,sym ,val ,doc))))

(defgroup whitespace nil
  "Check for five different types of whitespaces in source code.

1. Leading space \(empty lines at the top of a file\).
2. Trailing space \(empty lines at the end of a file\).
3. Indentation space \(8 or more spaces at beginning of line, that should be
		      replaced with TABS\).
4. Spaces followed by a TAB. \(Almost always, we never want that\).
5. Spaces or TABS at the end of a line.

Whitespace errors are reported in a buffer, and on the modeline.

Modeline will show a W:<x> to denote a particular type of whitespace, where
`x' can be one \(or more\) of:

e - End-of-Line whitespace.
i - Indentation whitespace.
l - Leading whitespace.
s - Space followed by Tab.
t - Trailing whitespace.

"
  ;; Since XEmacs doesn't have a 'convenience group, use the next best group
  ;; which is 'editing?
  :group (if whitespace-running-emacs 'convenience 'editing))

(defcustom whitespace-auto-cleanup nil
  "Setting this will cleanup a buffer automatically on finding it whitespace
unclean.

Use the emacs `customize' command to set this.
"
  :type  'boolean
  :group 'whitespace)

(defcustom whitespace-silent nil
  "Setting this to t will cause the whitespace error buffer not to pop
up. All whitespace errors will be shown only in the modeline.

Note that setting this may cause all whitespaces introduced in a file to go
unnoticed when the buffer is killed, unless the user visits the `*Whitespace
Errors*' buffer before opening \(or closing\) another file.

Use the emacs `customize' command to set this.
"
  :type 'boolean
  :group 'whitespace)

(defcustom whitespace-modes '(ada-mode asm-mode autoconf-mode awk-mode
				       c-mode c++-mode cc-mode cperl-mode
				       electric-nroff-mode emacs-lisp-mode
				       f90-mode fortran-mode html-mode
				       html3-mode java-mode jde-mode
				       ksh-mode latex-mode LaTeX-mode
				       lisp-mode m4-mode makefile-mode
				       modula-2-mode nroff-mode objc-mode
				       pascal-mode perl-mode prolog-mode
				       python-mode scheme-mode sgml-mode
				       sh-mode shell-script-mode
				       simula-mode tcl-mode tex-mode
				       texinfo-mode vrml-mode xml-mode)

  "Modes that we check whitespace in. These are mostly programming and
documentation modes. But you may add other modes that you want whitespaces
checked in by adding something like the following to your `.emacs':

\(setq whitespace-modes \(cons 'my-mode \(cons 'my-other-mode
					    whitespace-modes\)\)

Or, alternately, you can use the Emacs `customize' command to set this.
"
  :group 'whitespace)

(if whitespace-running-emacs (require 'timer))

(defvar whitespace-all-buffer-files nil
  "An associated list of all buffers
and theirs files checked for whitespace cleanliness. This is to enable
periodic checking of whitespace cleanliness in the files visited by the
buffers.")

(defvar whitespace-rescan-timer nil
  "Timer object that will be set to
rescan the files in Emacs buffers that have been modified.")

(defcustom whitespace-rescan-timer-time 60
  "seconds after which
`whitespace-rescan-files-in-buffers' will check for modified files in Emacs
buffers."
  :type 'integer
  :group 'whitespace)


;; Tell Emacs about this new kind of minor mode
(make-variable-buffer-local 'whitespace-mode)
(put 'whitespace-mode 'permanent-local nil)
(set-default 'whitespace-mode nil)

(make-variable-buffer-local 'whitespace-mode-line)
(put 'whitespace-mode-line 'permanent-local nil)
(set-default 'whitespace-mode-line nil)

(if (not (assoc 'whitespace-mode minor-mode-alist))
    (setq minor-mode-alist (cons '(whitespace-mode whitespace-mode-line)
				 minor-mode-alist)))

(defun whitespace-check-whitespace-mode (&optional arg)
  (if (null whitespace-mode)
      (setq whitespace-mode
	    (if (or arg (member major-mode whitespace-modes))
		t
	      nil))))

(defun whitespace-buffer (&optional quiet)
  "Find five different types of white spaces in buffer:

1. Leading space \(empty lines at the top of a file\).
2. Trailing space \(empty lines at the end of a file\).
3. Indentation space \(8 or more spaces, that should be replaced with TABS\).
4. Spaces followed by a TAB. \(Almost always, we never want that\).
5. Spaces or TABS at the end of a line.

Check for whitespace only if this buffer really contains a non-empty file
and:
1. the major mode is one of the whitespace-modes, or
2. `whitespace-buffer' was explicitly called with a prefix argument.
"
  (interactive)
  (whitespace-check-whitespace-mode current-prefix-arg)
  (if (and buffer-file-name (> (buffer-size) 0) whitespace-mode)
      (progn
	(whitespace-check-buffer-list (buffer-name) buffer-file-name)
	(whitespace-tickle-timer)
	(if whitespace-auto-cleanup
	    (if (and (not quiet) buffer-read-only)
		(message "Can't Cleanup: %s is read-only." (buffer-name))
	      (whitespace-cleanup))
	  (let ((whitespace-leading (whitespace-buffer-leading))
		(whitespace-trailing (whitespace-buffer-trailing))
		(whitespace-indent (whitespace-buffer-search
				    whitespace-indent-regexp))
		(whitespace-spacetab (whitespace-buffer-search
				      whitespace-spacetab-regexp))
		(whitespace-ateol (whitespace-buffer-search
				   whitespace-ateol-regexp))
		(whitespace-errmsg nil)
		(whitespace-error nil)
		(whitespace-filename buffer-file-name)
		(whitespace-this-modeline ""))

	    ;; Now let's complain if we found any of the above.
	    (setq whitespace-error (or whitespace-leading whitespace-indent
				       whitespace-spacetab whitespace-ateol
				       whitespace-trailing))

	    (if whitespace-error
		(progn
		  (setq whitespace-errmsg
			(concat whitespace-filename " contains:\n"
				(if whitespace-leading "Leading whitespace\n")
				(if whitespace-indent
				    (concat "Indentation whitespace"
					    whitespace-indent "\n"))
				(if whitespace-spacetab
				    (concat "Space followed by Tab"
					    whitespace-spacetab "\n"))
				(if whitespace-ateol
				    (concat "End-of-line whitespace"
					    whitespace-ateol "\n"))
				(if whitespace-trailing
				    "Trailing whitespace.\n")
				"\ntype "
				"`whitespace-cleanup' to cleanup the file."))
		  (setq whitespace-this-modeline
			(concat (if whitespace-ateol "e")
				(if whitespace-indent "i")
				(if whitespace-leading "l")
				(if whitespace-spacetab "s")
				(if whitespace-trailing "t")))
		  (setq whitespace-mode-line
			(concat " W:" whitespace-this-modeline))
		  (whitespace-force-mode-line-update)))
	    (save-excursion
	      (get-buffer-create whitespace-errbuf)
	      (kill-buffer whitespace-errbuf)
	      (get-buffer-create whitespace-errbuf)
	      (set-buffer whitespace-errbuf)
	      (if whitespace-errmsg
		  (progn
		    (insert whitespace-errmsg)
		    (if (not (and quiet whitespace-silent))
			(display-buffer whitespace-errbuf t))
		    (if (not quiet)
			(message "Whitespaces: [%s] in %s"
				 whitespace-this-modeline
				 whitespace-filename)))
		(if (not quiet)
		    (message "%s clean" whitespace-filename)))))))))

(defun whitespace-region (s e)
  "To check a region specified by point and mark for whitespace errors."
  (interactive "r")
  (save-excursion
    (save-restriction
      (narrow-to-region s e)
      (whitespace-buffer))))

(defun whitespace-cleanup ()
  "To cleanup the five different kinds of whitespace problems that
are defined in \\[whitespace-buffer]"
  (interactive)
  ;; If this buffer really contains a file, then run, else quit.
  (whitespace-check-whitespace-mode current-prefix-arg)
  (if (and buffer-file-name whitespace-mode)
      (let ((whitespace-any nil)
	    (whitespace-tabwith 8)
	    (whitespace-tabwith-saved tab-width))

	;; since all printable TABS should be 8, irrespective of how
	;; they are displayed.
	(setq tab-width whitespace-tabwith)

	(if (whitespace-buffer-leading)
	    (progn
	      (whitespace-buffer-leading-cleanup)
	      (setq whitespace-any t)))

	(if (whitespace-buffer-trailing)
	    (progn
	      (whitespace-buffer-trailing-cleanup)
	      (setq whitespace-any t)))

	(if (whitespace-buffer-search whitespace-indent-regexp)
	    (progn
	      (whitespace-indent-cleanup)
	      (setq whitespace-any t)))

	(if (whitespace-buffer-search whitespace-spacetab-regexp)
	    (progn
	      (whitespace-buffer-cleanup whitespace-spacetab-regexp "\t")
	      (setq whitespace-any t)))

	(if (whitespace-buffer-search whitespace-ateol-regexp)
	    (progn
	      (whitespace-buffer-cleanup whitespace-ateol-regexp "")
	      (setq whitespace-any t)))

	;; Call this recursively till everything is taken care of
	(if whitespace-any (whitespace-cleanup)
	  (progn
	    (message "%s clean" buffer-file-name)
	    (setq whitespace-mode-line nil)
	    (whitespace-force-mode-line-update)))
	(setq tab-width whitespace-tabwith-saved))))

(defun whitespace-cleanup-region (s e)
  "To do a whitespace cleanup on a region specified by point and mark."
  (interactive "r")
  (save-excursion
    (save-restriction
      (narrow-to-region s e)
      (whitespace-cleanup))
    (whitespace-buffer t)))

(defun whitespace-buffer-leading ()
  "Check to see if there are any empty lines at the top of the file."
  (save-excursion
    (let ((pmin nil)
	  (pmax nil))
      (goto-char (point-min))
      (beginning-of-line)
      (setq pmin (point))
      (end-of-line)
      (setq pmax (point))
      (if (equal pmin pmax)
	  t
	nil))))

(defun whitespace-buffer-leading-cleanup ()
  "To remove any empty lines at the top of the file."
  (save-excursion
    (let ((pmin nil)
	  (pmax nil))
      (goto-char (point-min))
      (beginning-of-line)
      (setq pmin (point))
      (end-of-line)
      (setq pmax (point))
      (if (equal pmin pmax)
	  (progn
	    (kill-line)
	    (whitespace-buffer-leading-cleanup))))))

(defun whitespace-buffer-trailing ()
  "Check to see if are is more than one empty line at the bottom."
  (save-excursion
    (let ((pmin nil)
	  (pmax nil))
      (goto-char (point-max))
      (beginning-of-line)
      (setq pmin (point))
      (end-of-line)
      (setq pmax (point))
      (if (equal pmin pmax)
	  (progn
	    (goto-char (- (point) 1))
	    (beginning-of-line)
	    (setq pmin (point))
	    (end-of-line)
	    (setq pmax (point))
	    (if (equal pmin pmax)
		t
	      nil))
	nil))))

(defun whitespace-buffer-trailing-cleanup ()
  "Delete all the empty lines at the bottom."
  (save-excursion
    (let ((pmin nil)
	  (pmax nil))
      (goto-char (point-max))
      (beginning-of-line)
      (setq pmin (point))
      (end-of-line)
      (setq pmax (point))
      (if (equal pmin pmax)
	  (progn
	    (goto-char (1- pmin))
	    (beginning-of-line)
	    (setq pmin (point))
	    (end-of-line)
	    (setq pmax (point))
	    (if (equal pmin pmax)
		(progn
		  (goto-char (1- (point-max)))
		  (beginning-of-line)
		  (kill-line)
		  (whitespace-buffer-trailing-cleanup))))))))

(defun whitespace-buffer-search (regexp)
  "Search for any given whitespace REGEXP."
  (let ((whitespace-retval ""))
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward regexp nil t)
	(setq whitespace-retval (format "%s %s " whitespace-retval
					(match-beginning 0))))
      (if (equal "" whitespace-retval)
	  nil
	whitespace-retval))))

(defun whitespace-buffer-cleanup (regexp newregexp)
  "Search for any given whitespace REGEXP and replace it with the NEWREGEXP."
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward regexp nil t)
      (replace-match newregexp))))

(defun whitespace-indent-cleanup ()
  "Search for any 8 or more whitespaces at the beginning of a line and
replace it with tabs."
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward whitespace-indent-regexp nil t)
      (let ((column (current-column))
	    (indent-tabs-mode t))
	(delete-region (match-beginning 0) (point))
	(indent-to column)))))

;; Force mode line updation for different Emacs versions
(defun whitespace-force-mode-line-update ()
  "To Force the mode line update for different flavors of Emacs."
  (if whitespace-running-emacs
      (force-mode-line-update)		; Emacs
    (redraw-modeline)))			; XEmacs

(defun whitespace-check-buffer-list (buf-name buf-file)
  (if (and whitespace-mode (not (member (list buf-file buf-name)
					whitespace-all-buffer-files)))
      (add-to-list 'whitespace-all-buffer-files (list buf-file buf-name))))

(defun whitespace-tickle-timer ()
  (if (not whitespace-rescan-timer)
      (setq whitespace-rescan-timer
	    (if whitespace-running-emacs
		(run-at-time nil whitespace-rescan-timer-time
			     'whitespace-rescan-files-in-buffers)
	      (add-timeout whitespace-rescan-timer-time
			   'whitespace-rescan-files-in-buffers nil
			   whitespace-rescan-timer-time)))))

(defun whitespace-rescan-files-in-buffers (&optional arg)
  "Check to see if all the files that are whitespace clean are
actually clean still, if in buffers, or need rescaning."
  (let ((whitespace-all-my-files whitespace-all-buffer-files)
	buffile	bufname thiselt buf)
    (if (not whitespace-all-my-files)
	(progn
	  (if whitespace-running-emacs
	      (cancel-timer whitespace-rescan-timer)
	    (disable-timeout whitespace-rescan-timer))
	  (setq whitespace-rescan-timer nil))
      (while whitespace-all-my-files
	(setq thiselt (car whitespace-all-my-files))
	(setq whitespace-all-my-files (cdr whitespace-all-my-files))
	(setq buffile (car thiselt))
	(setq bufname (cadr thiselt))
	(setq buf (get-buffer bufname))
	(if (buffer-live-p buf)
	    (save-excursion
	      ;;(message "buffer %s live" bufname)
	      (set-buffer bufname)
	      (if whitespace-mode
		  (progn
		    ;;(message "checking for whitespace in %s" bufname)
		    (if whitespace-auto-cleanup
			(progn
			  ;;(message "cleaning up whitespace in %s" bufname)
			  (whitespace-cleanup))
		      (progn
			;;(message "whitespace-buffer %s." (buffer-name))
			(whitespace-buffer t))))
		;;(message "Removing %s from refresh list" bufname)
		(whitespace-refresh-rescan-list buffile bufname)))
	  ;;(message "Removing %s from refresh list" bufname)
	  (whitespace-refresh-rescan-list buffile bufname))))))

(defun whitespace-refresh-rescan-list (buffile bufname)
  "Refresh the list of files to be rescaned."
  (if whitespace-all-buffer-files
      (progn
	(setq whitespace-all-buffer-files
	      (delete (list buffile bufname) whitespace-all-buffer-files)))
    (progn
      (if (and whitespace-running-emacs (timerp whitespace-rescan-timer))
	  (cancel-timer whitespace-rescan-timer))
      (if (and (not whitespace-running-emacs) whitespace-rescan-timer)
	  (disable-timeout whitespace-rescan-timer))
      (if whitespace-rescan-timer
	  (setq whitespace-rescan-timer nil)))))

(provide 'whitespace)

;;; whitespace.el ends here